RESEARCH ON DAMAGE CONSTITUTIVE MODEL OF ENGINEERED CEMENTITIOUS COMPOSITES UNDER UNIAXIAL TENSION

The effects of polyvinyl alcohol (PVA) fiber volume and water-binder ratio on tensile mechanical properties (cracking strain, cracking stress, peak strain, peak stress, ultimate strain and stress-strain relationship) of Engineered Cementitious Composites (ECC) were investigated through uniaxial tensile test. Based on test results, the damage evolution mechanism of ECC during the pre-cracking stage, strain hardening stage and strain softening stage of uniaxial tension process was discussed from the perspective of damage mechanics. Furthermore, based on the ECC tensile damage evolution mechanism, the ECC tensile damage constitutive model was proposed, and the calculation method of the model parameters was given. The analysis result shows that the ECC tensile damage evolution curve calculated by the proposed model can reflect the whole process of ECC damage more reasonably. Finally, Comparisons between the tensile stress-strain relationship curve calculated by the proposed model and the test curve demonstrate that the model can reasonably describe the nonlinear tensile stress-strain relationship of ECC and has good accuracy.